The invention relates to a modular transformer that can be used in a power substation for power transmission in the high and medium voltage ranges and in a distribution power panel for low voltage. The transformer utilizes two parallel iron cores with a rotational shifter located between the cores. The position of the shifter determines the amount of voltage reduction between the primary and secondary windings of the transformer.
Several transformers according to the invention can be located in different points of a network transmission line to control the uniform power distribution to the customers. The transformer can be made in different dimensions for a wide range of powers, for a single phase and two phase as well as a three phase system, without limitation of size and dimension, because all components can made by customer design or bought in the market.